| According to the problems of low content of lipid-lowering health care ingredients,low color price and instability in Hongqu Huangjiu,this paper aims to improve the content of lovastatin and color stability in Hongqu Huangjiu.Monascus strains with high content of lovastatin and monascus pigment were isolated and screened from various Hongqu samples,and using mutation breeding improved the ability of Monascus strains producing lovastatin and monascus pigment.Finally,the content of lovastatin and color value in Hongqu Huangjiu were improved greatly.In order to improve the stability of color price and the fading phenomenon of shelf life of Hongqu Huangjiu,the factors influencing color price of Hongqu Huangjiu in dark storage were studied.The main results in this paper were as follows:1.Objective to isolate and screen Monascus strains from Hongqu in main producing areas of China.Forty-nine strains of Monascus were isolated from 40 Hongqu samples.Among them,41 strains were M.purpureus,5 strains were M.kaoliang,2 strains were M.pilosus and one strain was M.ruber.Monascus purpureus strain H5-3 was obtained by solid-state fermentation.The yield of lovastatin was 17.90 mg·g-1,the color value was 3195.27?g·g-1.,and the activities of glucoamylase,liquefying enzyme and acid protease were 2514.26 U·g-1,0.32 U·g-1and300.19 U·g-1 respectively.It can be used in the production of Hongqu Huangjiu.2.The ability of Monascus H5-3 to produce lovastatin and monascus pigment was improved by mutation breeding.Monascus H5-3 was mutated by UV,and 10 positive mutants were obtained from 82 mutants by solid-state fermentation.A positive mutant Z-27 with excellent lovastatin,monascus pigment and enzyme activity was obtained by rescreening.The content of lovastatin of mutan Z-27 was 23.41 mg·g-1,increasing by 30.78%.Strain Z-27 was mutated by atmospheric and room temperature plasma.Four positive mutants were obtained from 47 mutants by solid-state fermentation.A stable genetic strain W-4 with high yield of lovastatin and monascus pigment was obtained by rescreening.The content of lovastatin was32.47 mg·g-1,compared with strain Z-27 and strain H5-3,the yield increased by 38.70%and81.39%,and the color value was 4638.18?g·g-1.The activities of glucoamylase,liquefying enzyme and acid protease were 2255.96 U·g-1,0.35 U·g-1 and 270.81 U·g-1,respectively,and the strain did not produce citrinin.3.Hongqu Huangjiu with high lovastatin was brewed with red koji W-4 as starter.Strain H5-3 and W-4 were applied to the brewing of 3 L system Hongqu Huangjiu respectively.By comparing the physical and chemical indexes,flavor substances and functional substances,the indexes of Hongqu Huangjiu brewed by strain W-4 met the national standard of Huangjiu,and the content of lovastatin was significantly higher than that of strain H5-3(P<0.05).Therefore,By using strain W-4 to brew rice wine in 100 L fermentor system,the content of lovastatin was115.02 mg·L-1,the color value was 29.28?·m L-1,and the content of lovastatin in each drinking unit was 7.05 mg.According to the stability of lovastatin and color value in Hongqu Huangjiu,the content of lovastatin did not decrease significantly after 6 months of storage at dark room temperature,but the color value decreased by 64.10%,and the stability was poor.4.In order to extend the shelf life and improve the color instability of Hongqu Huangjiu,the factors influencing the color stability of Hongqu Huangjiu under dark conditions were analyzed.By exploring the key factors affecting the color stability of red koji wine under dark storage conditions,it was found that the temperature was the primary factor affecting the color instability.After the red koji wine was heated at 60?,80?and 100?for 2 h,the storage rate of red pigment was 88.97%,71.86%and 58.18%respectively.The red koji wine was stored at4?,25?and 37?in dark for 90 days,the storage rate of red pigment was 72.01%,39.13%and 29.90%respectively.The acid components such as acetic acid and lactate in red starter wine also affect the color instability of red starter wine.After 90 days of storage,the preservation rate of red pigment decreased by 17.56%and 15.68%respectively.The degradation of red pigment was slowed down by alcohol and catechins in wine,and the stability of red pigment increased by 91.44%and 47.43%after 90 days storage at 37?with 28%(V/V)ethanol and 8%(m/V)catechins.So the color stability of Hongqu Huangjiu stored in dark at 4?was 84.03%and 140.83%higher than that at room temperature(25?and 37?).In conclusion,this study isolated and screened Monascus strains with high content of lovastatin and monascus pigment from Fujian,Guangdong,Zhejiang and other places,and effectively improved the content of lovastatin in Monascus by UV-ARTP mutation technology to improve the content of lovastatin in Hongqu yellow rice wine and enhance the red color of wine.It is helpful to promote the application of functional Hongqu in food industry And it is of great significance to improve the functional quality and extend the shelf life of Hongqu Huangjiu. |
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